1. Field of the Invention
The present invention relates to processing used for a liquid crystal projector.
2. Description of the Prior Art
In recent years, in liquid crystal projectors, a projecting lamp for projecting an image written into a liquid crystal cell on a screen has been increased in luminance for improving its brightness performance. Further, there is a tendency to miniaturize the liquid crystal projector.
On the other hand, an electric circuit in the liquid crystal projector is required to cope with high resolution and enhance its function by increasing the performance of a personal computer. A semiconductor device having a high integration degree tends to be used, and its power supply voltage is low.
Used as the projecting lamp for projecting the image written into the liquid crystal cell on the screen are a metal halide projecting lamp and a very high pressure mercury projecting lamp. When the lamp is turned on, noises occur. The noises are not restrained as the luminance of the projecting lamp is increased. On the contrary, the noises are liable to be increased. Further, as the liquid crystal projector is miniaturized, the projecting lamp tends to approach the electric circuit.
As the power supply voltage of the electric circuit using the semiconductor having a high integration degree, 3.3 volts have been in the main current. In this state, the noises at the time when the projecting lamp is turned on may affect the electric circuit, resulting in malfunction. When a microcomputer malfunctions, the malfunction may not, in some cases, be recovered unless the power supply is turned off once or the microcomputer is reset.
In general setting, this state can be recovered by turning the power supply on after turning it off once or pressing a reset switch as in a recent personal computer. In the case of the liquid crystal projector, however, when the operation is performed, the projecting lamp is turned off once. The metal halide projecting lamp and the very high pressure mercury projecting lamp cannot be turned on again immediately after being turned off once. One to two minutes must be waited for until the temperature in the projecting lamp is reduced.
The same is true for a case where the reset switch is provided to reset the microcomputer. The liquid crystal projector enters a standby state where the projecting lamp is turned off. When an attempt to operate the liquid crystal projector again is made, one or two minutes must be waited for.
An object of the present invention is to provide a liquid crystal projector capable of immediately recovering, when an abnormality occurs in the liquid crystal projector, the abnormality and capable of solving trouble in waiting for one to two minutes until the temperature of a projecting lamp is reduced.
In a liquid crystal projector using a microcomputer as a control unit of the liquid crystal projector and comprising a projecting lamp for projecting an image written into a liquid crystal cell and a cooling fan for the projecting lamp, a first liquid crystal projector according to the present invention is characterized by comprising a reset switch for resetting the operation of the microcomputer; and abnormality recovery means for initializing, when the liquid crystal projector is in a power on mode, other circuits and the microcomputer without stopping the projecting lamp and the cooling fan when the reset switch is turned on.
In a liquid crystal projector using a microcomputer as a control unit of the liquid crystal projector and comprising a projecting lamp for projecting an image written into a liquid crystal cell and a cooling fan for the projecting lamp, a second liquid crystal projector according to the present invention is characterized by comprising a reset switch for resetting the operation of the microcomputer; and an abnormality recovery circuit for initializing, when the liquid crystal projector is in a power on mode, other circuits and the microcomputer without stopping the projecting lamp and the cooling fan when the reset switch is turned on.
According to the present invention, even when an abnormality occurs in the liquid crystal projector, the abnormality can be recovered without tuning the projecting lamp off. Accordingly, the abnormal state can be quickly recovered without requiring a waiting time period for cooling the projecting lamp.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.